The present disclosure relates to a TFT-LCD (Thin Film Transistor Liquid Crystal Display), especially to a test circuit and test method for detecting an electrical defect in TFT-LCD.
In the flat display technology, the TFT-LCD has characteristics such as small size, low power consumption, no radiation, relatively low manufacturing cost and so on, and dominates the current flat display market.
With LCD (Liquid Crystal Display) production being enlarged increasingly, the product performance is improved increasingly, and the defect detection for products plays an important role in the whole production process.
In the detection process of TFT-LCD, an electrical defect and an optical defect can be distinguished from each other effectively by using a DC/DC (direct current-to-direct current power supply) test method, and thereby the location range of a defect in the forepart project can be reduced greatly, thus providing a great help for looking rapidly for the defect mechanism and countermeasure.
However, after knowing that one display screen contains an electrical defect, there is still no perfect method in the current mass production test about how to distinguish whether it is related to capacitance or TFT. The current test method after the liquid crystal cell process, like the test method and test mechanism of a terminal, can detect various optical and electrical defects of a LCD perfectly, but on the premise of knowing that the defect is resulted from an electrical defect, it is still unable to perfectly distinguish whether it is related to capacitance or TFT. Especially some uneven-light-and-dark-mark (Mura) type defects, when arising in a large scale, can not be distinguished out in time, which leads to slowness of the defect location, thereby resulting in a great loss.